This invention relates to an unmanned conveying control system useful in a work area such as a warehouse or a factory.
Unmanned conveying system using a conveyor belt or a stacker crane have been known for conveying a desired load between a work area such as a warehouse or a factory and a predetermined position (e.g. a gateway of a warehouse or a certain position on a manufacture line of a factory). The prior art system using the conveyor conveys a load on a fixed conveyer line and loads or unloads the load at a predetermined position by means of a loading and unloading machine. In the prior art system using a stacker crane, racks are provided in a storage place in a warehouse or a factory and loading and unloading operations are made by a stacker crane which is displaceable along the racks. These prior art systems, however, are large scale systems in which change of the conveyor line cannot be readily made once it has been established. Besides, the conveyor lines of these prior art systems occupy a large space so that space cannot be utilized efficiently for storage of goods.
There has also been used an absolute position control system in which a ground equipment is provided for enabling a loading and unloading vehicle to detect the position of a rack or a loading table so as to inform the vehicle of a loading and unloading place. This system has the disadvantage that a large ground equipment and a large amount of provision work are required if there are many loading and unloading positions resulting in increase in the cost.
Further, in the prior art systems, a position instruction device is provided for determining a loading and unloading position and a control signal is applied to this device from outside for guiding the vehicle to a predetermined lane and shelf of rack, and this requires extremely complicated device and control.